For a vehicle having an internal combustion engine mounted thereon, a technique of automatically starting and stopping the internal combustion engine has been known. In such a vehicle, at the time of cranking to start the internal combustion engine, it is possible that power is transmitted to driving wheels to cause a feeling that the vehicle is lurching forward, or causing downward slip if on a sloping road.
In view of such a problem, Japanese Patent Laying-Open No. 2005-153823 (PTL 1) discloses a vehicle in which automatic stop of the internal combustion engine is facilitated and the feeling of lurching or moving downward on a sloping road is reduced at the time of automatic start. In the vehicle, if automatic stop conditions are satisfied, an internal combustion engine that is operating is automatically stopped, and if automatic start conditions are satisfied, the internal combustion engine that has been automatically stopped is automatically started, and the vehicle includes: a cylinder hydraulic pressure adjusting means allowing adjustment of cylinder hydraulic pressure of a brake wheel cylinder; brake pressure condition changing means for changing brake pressure condition as one of the automatic stop conditions based on the state of the cylinder hydraulic pressure adjusting means; and cylinder hydraulic pressure control means controlling the cylinder hydraulic pressure adjusting means such that the cylinder hydraulic pressure of the brake wheel cylinder is adjusted based on the state of cylinder hydraulic pressure adjusting means, when the automatic stop conditions including the brake pressure condition changed by the brake pressure changing means are satisfied and the internal combustion engine is automatically stopped.
According to the disclosure of the literature above, in the vehicle, the brake hydraulic pressure is increased to attain appropriate hydraulic pressure after automatic stop and, therefore, the feeling of lurching of the vehicle can be reduced at the time of automatic start.
Further, recently, as one measure to address environmental problems, hybrid vehicles running with the driving force from an internal combustion engine and a driving electric motor are attracting attention. In such a hybrid vehicle also, the internal combustion engine may be automatically started or stopped.